LINQ-将列表转换为字典，并将值作为列表 [英] LINQ - Convert List to Dictionary with Value as List

问题描述

我有一个

List<MyObject> 

我从数据库中检索到的

.但是，我希望通过MyObject中的属性将其设置为分组目的.用LINQ将列表投射到的最佳方法是什么?

that I retrieve from the database. However, I would like it keyed by a property in MyObject for grouping purposes. What is the best way with LINQ to cast my list to:

Dictionary<long, List<MyObject>>

我有以下内容:

myObjectList.ToDictionary(x => x.KeyedProperty)

但是它返回:

Dictionary<long, MyObject>

推荐答案

听起来您想按KeyedProperty对MyObject实例进行分组，然后将该分组放入Dictionary<long,List<MyObject>>中.如果是这样，请尝试以下操作

It sounds like you want to group the MyObject instances by KeyedProperty and put that grouping into a Dictionary<long,List<MyObject>>. If so then try the following

List<MyObject> list = ...;
var map = list
  .GroupBy(x => x.KeyedProperty)
  .ToDictionary(x => x.Key, x => x.ToList());

这篇关于LINQ-将列表转换为字典，并将值作为列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！